Do keep in mind that SQL Server databases are not backward compatible, as such ensure that your new SQL Server instance is on the same version or on a higher version as your current Lansweeper database instance.
Keep in mind that it would be best practice to stop the Lansweeper server services on your scanning servers and your web server (IIS Express or IIS) service on your Lansweeper web server prior to making any changes to your Lansweeper components, and then restarting the services afterwards when the upgrade is complete.